Battle ensues after 'terrorists' set off bomb under car

DAMASCUS, Syria (CNN) -- Four people, including a passer-by, were killed during an hourlong battle between security forces and gunmen Tuesday evening in the diplomatic district of the Syrian capital, an Interior Ministry source told the news agency SANA.

The gunfight ensued when security forces arrived on the scene after "a group of terrorists" set off a bomb under a parked car on Meze Road, the source said.

The attackers also threw grenades at the security forces, the source said.

Two of the four attackers were killed and two were captured critically wounded, the source said.

One member of the security force and a Syrian woman who happened to be in the area also were killed, a security source said.

Hours after the attack, Syrian state-owned television showed video of grenades, gas cylinders and bags of yellow powder found in a house said to be used by the group that set off the bomb.

At least six explosions preceded the gunfire at about 8 p.m. (1 p.m. ET) in an area between the Iranian and Canadian embassies and near the residence of the British ambassador to Syria, according to witnesses.

A building that once housed the United Nations peacekeeping mission was heavily damaged, witnesses said. Although it is still called a U.N. building, no U.N. employees work there, said a U.N. spokesman in New York.

The spokesman said all U.N. staff members in Syria were accounted for and unhurt and no damage is reported to any current U.N. buildings.

Witnesses said a restaurant also was heavily damaged.

The gunbattle took place on the street in the rear of the Iranian Embassy, according to a source at the British Embassy. The source said no Britons were injured.

A senior State Department official said the battle was not near the U.S. Embassy.

Iranian TV reported there was no damage to Iran's embassy and no injuries among the Iranians who work there. The report also said three people, armed with grenades, had been arrested.

A doctor told CNN at least five civilians have been taken to hospitals for treatment and a call was issued for doctors to report to emergency rooms.

The Interior Ministry source blamed the incident on the atmosphere created by instability and confusion in security and politics in the region.

"The Syrian Republic ... is condemning this terrorist attack," the source said, contending it was meant to affect the stability and security of the country.

CNNArabic.com's Caroline Faraj in Dubai, United Arab Emirates, Shirzad Bozorgmehr in Tehran and Liz Neisloss in New York contributed to this report.